A MRAM (Magnetic Random Access Memory) is a magnetic memory chip using a magnetoresistive effect on the basis of a spin depending conduction phenomenon characteristic of a nanomagnet, and a nonvolatile memory that can hold memories without supplying electric power from the exterior. However, the MRAM is susceptible to an external magnetic field, and if a single chip is subjected to a magnetic field of 10 [Oe] or higher, there is a possibility of malfunction, such as erroneous writing. Therefore, in a magnetic memory chip device incorporating the MRAM, techniques providing a magnetic shield that protects the MRAM from the external magnetic field have been proposed (for example, refer to Patent Documents 1 to 9).    Patent Document 1: JP-A-2003-115578    Patent Document 2: JP-A-2004-47656    Patent Document 3: JP-A-2004-103071    Patent Document 4: JP-A-2004-193247    Patent Document 5: JP-A-2004-200185    Patent Document 6: JP-A-2004-207322    Patent Document 7: JP-A-2004-221288    Patent Document 8: JP-A-2004-221463    Patent Document 9: JP-A-2005-158985